Stabilization of edible oils and fats



Patented Jan. 19,1954 v 2,666,709

UNITED STATES PATENT "OFFICE asserts smmmzmouor iz-mere onis ANDFAT'S Robert H. Rosenwald, Western Springs, and Joseph A. Cheni'cek, Riverside, ;Ill. iassignors :tn

' Universal Oil Products Company, (Iliicago, Ill.I

a corporation :of Delaware No Drawing. Application October 24, 1945, Serial No. 24,318

21 Claims. (01.99-163) 2 This invention relates to the stabilization of 1y as typical representatives, the following are edible oils and fats and more particularly to the mentioned; linseed oil, menhaden oil, cod liver inhibition of the development of rancidity there oil, ,caster oil, olive oil, rapeseed :oil, coconut oil, palm oil, corn oil, sesame oil, peanut oil, .babassu Many compounds are known which will pre- 5 oil, butter, fat, lard, beef tallow, etc as '--wel1 as n fi pment of rancidity in e i e Oils hydrogenated oils and fats such as are sold unand vfats but practically all of them are unsuitder various trade names including Crisco,

tories, stores or in :the homes, before consumpable because they are either toxic and therefore Snowdrift, eta It is understood tha'to'ther cannot be used for stabilizing the edible oils and oils and fats maybe treated within the scope of fats, or else they impart bad odor and taste to .10 the present invention, including oils and fats such oils and :fats. Some of these compounds which have previously been subjected to various are so volatile they are removed from the oils treatments, such as blowing with air, heat treatand fats during cooking or in deep fat trying, ment, etc. 1

while others are relatively insoluble in oils and The novel inhibitor of the present invention fats. comprises 2-alkyl-4-alkoxy phenols of the .gen-

A very important feature of an inhibitor tor e 1 t u t r the stabilization of oils and fats is that the in- 0H hibitor carries over into the bakery products. 6' Many bakery products as, .ior example, crackers,

are kept for considerable periods of time in fac- .20

tion. These bakery goods tend to become rancid a I due to these long periodsof storage. While some L of the known inhibitors are very potent when .used in edible oils and fats, they do not have Wherein'R andIR," arealkylgroups.

this important property of carrying over into The alkyl groups substituted in the ring may the bakery goods and therefore are not comcomprise any alkyl groups such as methyl, ethyl, pletely satisfactory for the purpose intended. It propyl, 'isopropyl, butyl, isobutyl, sec-bu'tyll, tertis the object of the present invention to provide butyl, amyl, isoamyl, sec-amyl, ter't-amyl; etc.

.a novel classof inhibitors which will retard .de- Of these groups the tert-alkyl groups appear to teri'oration' of edible oils and fats'and also will vbe more effective in contributing to the inhibi- Ietard the development of ranc'idity in'the bakery tor potency of the resultant compound Likegoods. 4 wise, the groups of higher molecular weight con- In one specificem'bodiment the present inventribute to other desirable properties of the intlon relates to a process for stabilizing edible 'hibitor. The substituent group is preferably in oils and fats against rancidity which comprises the position ortho to the hydroxyl group. Some -inventionrelates to edible 'oils and fats 'nor- 'po'rated therein a-small amount of a compound lio incorporating therein a minor portion of a comcompounds having alkyl groups in the meta popound having the general structure sition may also have inhibiting value.

- on Particularly potent inhibitors comprise those 40 in which the alkoxy or ether group is in the &-

vposition. The alkyl group of this alkcxy substituent may comprise, for example, methyl,

ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl,

tert-butyl, amyl, iso-amyl, sec-amyl, tert-amyl;

Y egg, ancllniay boettihe same or difierent iron 11th:

. 0 er aky su s i uen groups In genera i fi g figg 5 g gg gg ggggzh the present may be said that the alkoxy groups of relatively low molecular weight, comprising methoxy or ethoxy groups, appear to have the strongest influence, although the other groups have considerhaving the general structure 'hereinbefore set able valuev forth. I. 1 The novel inhibitor of the present invention The edible oils and rats which may be stabilized may be p par d n any suitable manner. one

mally tending to become rancid having incor- .in accordance ,with the, present invention are particularly convenient method of preparing the .generally of l'animal and'resefiable origin. .Mere- ,6 hi i or. consists in alkvlatmahydroqui one ether and particularly a mono-alkyl ether with an olefin acting substance including an olefin, alcohol, ether, etc. For example, hydroquinonemonomethyl ether may be reacted at a temperature of '75 to 80 C. with a tertiary alcohol corresponding to the group to be substituted, using 85% phosphoric acid as the catalyst. The reaction mixture is stirred continuously until the reaction is complete. The mixture is then washed with water to remove the remaining acid and is extracted with 10% sodium hydroxide solution to remove the unreacted hydroquinone ether. The insoluble portion is distilled under reduced temperature and the resulting compound may be further purified by recrystallization.

The inhibitor of the present invention is added to the oils and fats in amounts of less than 1% by weight and generally below 0.01%. In most instances the amount of inhibitor utilized will be in the range of 0.0001% to 0.01%.

The following example is introduced to illustrate further the novelty and utility of the present invention but not with the intention of unduly limiting the same.

The inhibitor of the present invention was utilized in stabilizing lard which had a stability period of 5 hours as determined by the Swift test. This test is described in detail in the article by A. E. King, H. L. Roschen and W. H. Irwin, which appeared in the Oil and Soap, vol. X, No. 6, pages 105 to 109 (1933). In general, this test comprises bubbling air through a sample of the lard until rancidity is determined organoleptically and by peroxide values. I

0.005% by weight of 2-tert-butyl-4-methoxyphenol added to the lard increased the period of stability to 23 hours. The inhibitor was prepared by reacting tertiary butyl alcohol with hydroquinone mono-methyl ether at 80 C. in the presence of phosphoric acid catalyst. While it is difficult to actually correlate the period of rancidity as determined by this test with the days or months of storage in factories, stores or homes, it is generally considered that a stability period of 20 hours is usually suflicient for all practical purposes. One of the reasons why it is so difiicult to make this correlation is that the subsequent storage, and particularly in homes, is under varying conditions of temperature and humidity. For example, in some homes, the oils and fats may be placed in a spot exposed to the sun and thereby may be subjected to this heat or the oils may be placed in a damp atmosphere and thereby be adversely afiected.

An important property of the inhibitor of the present invention is that it carries over with the lard into the bakery goods and therebyretards the development of rancidity therein. In general, the bakery goods are tested for rancidity primarily by tasting, and it has been found that the bakery goods prepared with lard containing this inhibitor remained free from rancidity for a considerably longer period of time than the same bakery goods prepared with lard to which the inhibitor of the present invention had not been added. As herembefore set forth, this property is an important feature of inhibitors for edible oils and fats. 'For example, hydroquinone, which otherwise is a good inhibitor for edible 'oils'and fats, does not carry over into the bakery good and therefore is not as satisfactory'for commercial use.

- We claim as our invention:

rating therein a small amount of a compound having the general structure where R is a tertiary alkyl group and R is an alkyl group of less than three carbon atoms.

3. A process for stabilizing edible oils and fats against rancidity which comprises incorporating therewith a small amount of 2-tert-butyl-4- methoxy phenol.

4. A process for stabilizing oils and fats against rancidity which comprises incorporating therewith a small amount of 2-tert-butyl-4-ethoxyphenol.

5. A process forstabilizing edible oils and fats against rancidity which comprises incorporating therewith a small amount of 2-tert-amyl-4- methoxy phenol.

6. Edible fatty oils and fats normally tending to become rancid having incorporated therewith, in an amount sufiicient to retard rancidity development, an inhibitor having the general structure where R is a tertiary alkyl group and R, is an alkyl group of less than three carbon atoms.

7. Edible oils and fats normally tending to become rancid having incorporated therein, in an amount sufiicient to retard rancidity .develop ment, 2-tert-butyl-4-methoxy phenol.

8. Edible oils and fats normally tending to become rancid having incorporated therein, in an amount sumcient to retard rancidity development, 2-tert-buty1-4-ethoxy phenol.

9. Edible oils and fats'normally tending to become rancid having incorporated therein, in an amount sufficient to retard rancidity development, 2-tert-amyl-4-methoxy phenol.

10. A method of stabilizing animal and vegetable fats and oils against rancidity which comprises incorporating therein a small amount of a .2-tertiary-alkyl-4-alkoxyphenol.

11. A'method of stabilizing animal and vege table fats and oils against rancidity which comprises incorporating therein a small amount of a 2-tertiary-butyl-i-alkoxyphenol.

12. A method of stabilizing animal and vegetable fats and oils against rancidity which com- I prisesiincorporating therein a small amount 0 alkoxyphenol.

, 4-metho1iyphenol.

13. A method of stabilizing, animal and vegetable fats and oils against rancidity which'comprises incorporating therein a small amount of 2-tertiary-butyl-4-ethoxyphenol.

.14. Animal and vegetable fats and oils normally tending to become rancid having in'corpo-v I rated therein a -small amount of. a 2-tertiaryalkyl-i-alkoxyphenol.

a small amount of a 2-tertiary-butyl-4-alkoxyphenol.

15. Animal andvegetable' fats and oils normally tending to become rancid having incorporated therein a small amount of aZ-tertiary-butyl-4-o 4-ethoxyphenol.

18. As a composition of matter, lard containing a small amount of a 2-tertiary-a1kyl-4- alkoxyphenol.

l 19. As a; composition of matter, lard containing 20. As a composition of matter, lard containing "a small amount of 2-tertiary-butyl-4-methoxyphenol. V 21. As a, composition of matter, lard containing a small amount of 2-tertiary-butyl-i-ethoxy phenol. I

ROBERT H. ROSENWALD. JOSEPH A. CHENICEK.

References Cited in the file of this atent UNITED STATES PATENTS Number Name Date 2,050,689 Briod Aug. 11, 1936 2,124,749 Salzberg July 26, 1938 2,131,904 Salzberg Oct. 4, 1938 2,138,924 Jones Dec. 6, 1938 2,315,858 Johnston Apr. 6, 1943 

1. A PROCESS FOR STABILIZING EDIBLE FATTY OILS AND FATS AGAINST RANCIDITY WHICH COMPRISES INCOPORATING THEREIN A SMALL AMOUNT OF A COMPOUND HAVING THE GENERAL STRUCTURE 